Protective device for electric-cable joints.



P. TORCHIO.

PROTECTIVE DEVICE FOR ELECTRIC CABLE JOINTS.

APPLICATION FILED MAIL I3, IQI5- Patented Feb. 22; 1916.

PHILIP TORCHIO, OF NEW YORK, N. Y.

PROTECTIVE DEVICE FOR ELECTRIC-CABLE JOINTS.

Specification of Letters Iatent.

Patented Feb. 22, 1916.

Application filed March 13, 1915. Serial No. 14,078.

T 0 all whom it may concern Be it known that I, PHILIP ToRoHIo, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented a certain new and useful Improvement in Protective Devices for Elctric-Cable Joints, of which the following is a specification.'-

The invention is a device for preventing current leakage at a joint in an electric line conductor, and more particularly at the joints in the line conductors of cables.

The invention consists in the construction whereby the joint is immersed in a fluid insulating medium adapted to permeate the pervious wrapping of the joint, whereby said fluid after permeation of said wrapping is retained therein by a denser body of insulating material surrounding said wrapping, and whereby the joint is inclosed in two metallic sleeves united at their ends to one another, separated between said ends and electrically'connected at said ends to the cable sheath, whereby the potential on the said sleeves becomes that of the sheath and breaking down of insulation between said sleeve or ionization of air between them is prevented.

In the accompanying drawings-Figure 1 is a longitudinal section of my joint. Fig. 2 is a transverse section on the line w, w of Fig. 1. Fig. 3 is an enlarged longitudinal section of a portion of the joint insulation, wire gauze cover and twine wrapping. Fig. 4 is an enlarged transverse section of the same. Fig. 5 is a modified form of my device in which the wire gauze cover, twine wrapping and oil supply reservoir are omitted. Fig. 6 is a modified form of my device in which the wire gauze cover and twine wrapping are omitted and the oil reservoir changed in form.

' Similar numbers of reference indicate like parts.

My device is here shown applied to a cable containing a plurality of conductors 1, 2, 3, Fig. 2, each having the usual cover 4 of insulating tape and all inclosed in an outer insulating wrapping 5, the interstices being filled with jute, paper or other pervious insulating material 6. In the ordinary operation of making the joint, the lead sheath 7 of the cable is cut away for a sufiicient distance to expose the conductors and permit application of the wrappings, and afterward a lead sleeve 8 is placed over the joint' and connected by wiped solder 9 to the ends of the lead sheathing, thus hermeticallyin closing the joint. Through two holes left in the sleeve 8 a fluid insulating compound .adapted to permeate the interstices 1n the insulating wrappings and filling of the oint' is poured.

some of them-as, for example, paraffin have found that said fluid compounds do not operate efliciently. In

voids or openings are formed, due to the the insulating compound on hardeningwill,

crack under mechanical stresses, especially when the conductors carry heavy overload currents. The consequence is that, by reason of these cracks and voids and the ionization of air in them, a lowering of dielectric strength of the joint insulation takes place, so that electric lines transmitting high tension currents, especially if underground, have their weakest places at the joints and at the ends of. the sheathing 7 where connected to the joint covering sleeve 8.

I have succeeded in overcoming the foregoing difliculty by the following means: In Fig. 1, I show the usual lead covering sleeve 8, provided on its upper side with a reservoir 10 closed by a screw plug 11. I fill-the sleeve and reservoir with any suitable insulating oil or other liquid which is fluid at low temperature and preferably of a character which will combine with the material used in the body of the cable for permeating or embedding the insulating wrappings. This liquid I preferably force into the sleeve 8 under pressure sufficient to drive it into the interstices of the cable ends and into the joint wrappings and fillings. When the introduction of the liquid iscomplete, I permit it to fill the reservoir 10, which is finally closed. The oil in the reservoir then serves to supply any deficiency, in

the sleeve caused by absorption and breathing of the cable or the disturbance of the conductors carrying sudden overload currents, so that the joint insulation is not only thoroughly permeated at the outset, but continues submerged in a bath of insulating oil.

Instead of making the reservoir 10 in the form of a separate chamber communicating with the sleeve, as shown in Fig. 1, I may dispose the sleeve eccentrically on the joint, so that the greatest clearance will be uppermost, as shown at 12 in Fig. 6. In this way, I produce an additional holding space for the oil within the sleeve itself.

Where for any reason it is not desirable to keep the sleeve filled with a light fluid, such as oil, I may first cause the wrappings and filling of the joint to be permeated with said light fluid, as already described, and then afterward draw ofl the surplus liquid and substitute therefor an insulating compound of greater density than said liquid to fill the space between the joint and the sleeve. The dense compound then acts both as an insulator and'as a means of imprisoning the lighter fluid already in the inter stices of the filling and wrappings of the joint.

In order still more efl'ectually to prevent any failure of dielectric strength at the joint, I prefer to inclose the joint wrapping 5 in an envelop 13 of wire gauze, which is electrically connected at its ends a, b to the cut extremities of the lead sheathing on each side of the joint, so that there is a free conducting path between said sheathing extremities through said envelop. This wire gauze envelop, while permitting free access of liquid into the joint, has the same (ground) potential of the lead sheath.

Hence there can be no breaking down of the insulation between the gauze envelop and sleeve 8 even it cracks or voids happen to be formed therein. The gauze envelop can be secured in place by any suitable means-such as a permeable wrapping 14: of tape or twine. I may use this gauze envelop in conjunction with a fluid permeated joint and with fluid between joint and sleeve, as shown in Fig. 1, or with a fluid permeated joint and the annular space surrounding said joint filled with denser insulating compound, as described, or with a fluid permeated joint and simply an air space between joint and sleeve.

It is to be observed that the insulating fluid not only permeates the wrappings and fillings at the joint, but also percolates into the insulation of the cable ends exposed in order to make the joint. This is of practical importance, because it often happens that during the making of the joint, the exposure of said ends permits of the permeating liquid used in the original manufacture of the cable to bleed or run out, and a consequent failure of insulation at these points ensues. This I have found to be the cause of breakdowns which were apparently unaccountable. The new fluid put into the joint sleeve supplies this loss and effectually prevents the dificulty.

I claim:

1. An electric cable, comprising a metallic sheath and a line conductor having a joint, the said sheath being removed suificiently to expose said joint, and two metallic sleeves disposed one within the other and inclosing said joint: the said sleeves being insulated from said joint, united at their ends to one another, separated between said ends, and

3. An electric cable, comprising a sheath,

a line conductor having a joint, a body of pervious insulating material inclo'sing said joint, the said sheath being removed for a distance suihcient to expose said pervious body, a sleeve of impervious material of greater diameter than said body, inclosing the same and hermetically united at its ends to said cable sheath, and'an insulating fluid adapted to permeate said pervious body contained in the space between said body and said sleeve.

4. An electric cable, comprising a sheath, a line conductor having a joint, a body of pervious insulating material inclosing said joint, the said sheath being removed for a distance suflicient to expose said pervious body, a sleeve of impervious material of greater diameter than said body, inclosing the same and hermetically united at its ends to said cable sheath, a receptacle communicating with the interior of said sleeve, and an insulating fluid adapted to permeate said pervious body contained in said receptacle and the space between said body and said sleeve.

5. An electric cable, comprising a sheath, a line conductor having a joint, a body of pervious insulating material inclosing said joint, the said sheath being removed for a distance suflicient to expose said pervious body, a sleeve of impervious material of greater diameter than said body, the same and hermetically united at its ends to said cable sheath, an insulating fluid permeating said pervious body, and a mass of insulating material said fluid contained inthe space between said body and said sleeve.

6. An electric cable, comprising a metallic sheath, a line conductor having a joint, a

oody of pervious insulating material inclos- 1g said oint, an envelop of foraminated inc'losing conducting material inclosing said body, the said sheath being removed for a sufiicient distance to expose said envelop, and the said envelop being electrically connected at its ends to said sheath, a sleeve of greater diameter than said envelop, 'inclosing the same and hermetically united at its ends to said sheath, and an insulating fluid adapted to permeate said pervious ody contained in the space between said envelop and said sleeve.

7 An electric cable, comprising a metallic sheath, a line conductor having a joint, a body of pervious insulating material inclos ing said joint, an envelop of foraminated conducting material inclosing said body, the said sheath being removed for a suflicient distance to expose said envelop, and

the said envelop being electrically connected at its ends to said sheath, a wrapping of fibrous insulating material on said envelop, a sleeve of reater diameter than said envelop, inclosmg the same and hermetically united at its ends to said sheath, and an insulating fluid adapted to permeate said pervious bodycontained in the space between said envelop and said sleeve.

In testimony whereof I have aiiixed my signature in presence of two witnesses.

PHILIP TORCHIO.

Witnesses:

GEnrn Dn T. Pon'rna, MAY G. \BIOGARRY.

DISCLAIMER.

1,172,322.-Phalip Torohio, New York, N. Y. PROTECTIVE DEVICE FOR ELEOI'RIC- CABLE JOINTS. 7, Patent dated February 22, 1916. Disclaimer filed February 11, 1927, by the assignee, Thomas E. Murray. 5 Hereby makes disclaimer of the improvement described except for electric cables which comprise a line conductor, insulating wrapping permeated with insulating compound and a sheath of flexible inelastic metal constituting a. unitary product of manufacture and commerce which is portable and capable of being drawn through conduits; and except as to an insulating liquid which is fluid at ordinary working temperatures of such cables and .in quantity sufficient to supply at all times the demands made by the cable in use, and by the joint.

[07720403 Gazette March 1, 1927.] 

